ASTRONOMY OF THE NINETEENTH CENTURY. ; 3 i 



FIG. 192. THE "DUMB-BELL" NEBULA. 



with the larger, also by means of spiral convolutions. Fig. 191 will 

 serve to give some idea of the aspect which this nebula presents as 

 seen by Lord Rosse, who has also detected unmistakable indications 

 of a spiral structure in at least fourteen nebulae. In some other nebulae, 

 which had previously been described as possessing uniform round discs, 

 Lord Rosse found distinct appearances of an annular arrangement. 

 Fig. 192 represents the so-called "dumb-bell" nebula in the constel- 

 lation Vulpecula, as it is figured by Lord Rosse. It usually happens 

 that in very large telescopes the aspect of a nebula is different from 

 that which it presents in smaller instruments. In this case, for in- 

 stance, the name, which correctly enough expresses the form of the 

 object as seen in an ordinary telescope, ceases to be appropriate to 

 the appearance of the nebula when examined by the great reflector at 

 Parsonstown. The nebula represented in Fig. 193 is known as the 

 Great Nebula in Orion, and is one of the largest and most curious in 

 its configuration. It was discovered by Huyghens in 1656, and was 



